A breathing mask of the type mentioned above has become known from EP-A 304 641. The prior-art breathing mask has a fixed mask body made of a transparent material, with a circumferential mask edge delimiting the mask body, to which mask edge a flexible sealing edge is attached. The flexible sealing edge comes into contact with the face of a mask user.
The mask body itself is designed as a curved mask body in both the meridian direction and the circumferential direction and has a flat surface, which is used as a sight opening for the mask user, in the area of the eyes. A supply opening for consumable liquid is located in the mouth area of the mask body.
It is disadvantageous in the prior-art breathing mask that the mask user has low-distortion vision only within the flat surface of the mask body, as a result of which the useful facial field is limited to this area.
It is also disadvantages in terms of vision that cushion-like distortions of the image may occur as the angle of vision through the flat surface becomes increasingly oblique.
A breathing mask with a breathing filter has become known from DE-A-23 29 668; this breathing mask has a mask body made of a transparent plastic, which is in contact with the mask user's face along a sealing line extending over the forehead, the cheeks, and the chin. The mask body is curved in both the meridian and horizontal directions. Since the mask body fits the contours of the face when the breathing mask is put on, undefined curvatures may develop, which may lead to distortion of the image, at least at certain angles of vision. Such distortion can be disturbing by the mask user and reduces the suitability of the breathing mask for use.